"As many of you know I have endometriosis, a chronic condition that affects approximately 1 in 10 women's reproductive health," she wrote. "I am currently going through a rough patch with the illness and my body (along with my amazing doctors) let me know, in no uncertain terms, that it's time to rest. That's a hard thing to do, but I'm trying, because all I want is to make season 6 of 'Girls' the best one yet."

Lena wrote about her longtime struggle with endometriosis in her Lenny Letter newsletter this past November. She explained the condition in simple terms as "when the tissue that lines the uterus grows in other places in the body," clarifying, "This usually means on the ovaries, in the abdominal cavity, and on the bladder and major organs like the liver and kidneys (though, in rare cases, the errant tissue has been found as far away as the brain)."

Hey Beloved Pals,I just wanted to let you know that, while I am so excited for Girls to return on Feb 21, I won't be...

She wrote at length about her personal struggles with endometriosis, which can cause "pain, fatigue, nausea, gastrointestinal problems, and a host of other physical symptoms" including infertility. In her Lenny Letter, Dunham reflected on the times she'd been sidelined by her chronic condition.

As she noted in Monday's Instagram post, she's grateful she's able to prioritize her health. "I'm lucky enough to have support and backup from Jenni [Konner], Judd [Apatow] and the whole 'Girls' gang," she wrote. "So many women with this disease literally don't have the option of time off and I won't take it for granted."

Dunham signed off her post by "Wishing you all health & happiness, in whatever form suits you."
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